Flood early-warning Alarm Pack
- Description of Proposed Project This project is designed for villagers or passerby who may be exposed to great danger of unexpected flood discharge. This alarm pack sends alarm to persons lingered in Reservoir Downstream Riverbed, allows them enough time to take precautions.
- Hardware and software
2.1 Principle Blocks First the arduino shall detect the water level by means of captivity sensing. The capacitor value shall be changed into water level value. The the value shall be transmitted to mobile via Bluetooth Low Energy protocol , the mobile APP receive the value and compare with alarm threshold value such as 2 meters. Trigger the PubNub publishing service. Then the web site shall be response to the publish by subscribing to the channel. Update the present situation for everyone interested in this information. The website is http://floodalarm.byethost24.com/
2.2 Hardware Arduino 101 shall be used
3 Capacitor sensing principle The fundamental element required in the capacitive touch sensing application described is the variable capacitor itself. This capacitor should be easy to construct as well as sensitive to human touch in order to enable this as an alternative to mechanical buttons and switches. Such a touch sensitive sensor element can be constructed by “opening up” a capacitor structure so that the electric field can be interfered with by a conductive foreign object, in this case, a finger. The figure below shows the touch sensor.It would be same if the capacitive water level sensors since water pose larger dielectric constant of 78.36F/m . There are two methods of capacity sensor, Oscillator-Based Capacitive Measurement or Resistor-Based Capacitive Measurement, I use the later, using an external resistor to charge or discharge the given capacitive sensor. Using the port pins to charge or discharge the sensor cap, the internal Timer_A can be used to measure the corresponding charge or discharge time. Given a fixed external resistance to provide the charge/discharge path, the capacitance of the sensor can be measured.